This happens full screen with multiple monitor setup too. If you move your mouse to the far edge of the game screen that is shared and left or right click, it will change windows to what is on the second monitor. If you scroll, it will scroll whats on the second window (wont kick you into the pause screen though)
This is happening on linux as well, forgot to add it
Dealing with the same issue, I have completely uninstalled and reinstalled everything related to it but it just crashes, the only time it has started it when i used a mod launcher to repair the files, but even then it just crashes afterward.
It started right as the new ui was added for the movie.
"An error occurred" or "It won't let me join and says 'an error occurred'